Burning mouth syndrome (BMS) is an orofacial chronic pain disorder affecting approximately 2-3% of the population. It is associated with burning pain of the oral mucosa, particularly the tongue, buccal mucosa, hard palate, and lips. The disease is thought to have multifactorial influences, including of small fiber pathology, sex hormone levels, anxiety, and stress. However, the central nervous system (CNS) mechanisms of the disease remain largely unknown. In our ongoing work, we have found a link between ongoing pain levels in BMS and brain dysfunction in a small sample of patients. We propose a study that will take into account multiple potential CNS abnormalities that could explain the symptomatology of BMS. The study will include 40 patients with BMS and 20 healthy controls. The patients will include 20 with BMS type 1, in which patients describe increasing burning pain as the day progresses, and 20 with BMS type 2, which is associated with constant pain throughout the day. Participants will undergo testing for two days, which will include electroencephalograph (EEG), functional MRI, and quantitative sensory testing (QST). In each BMS patient, we will perform QST and EEG in the morning and in the afternoon to capture the effects of ongoing pain levels (which is expected to vary most in BMS type 1 patients). If our study is successful, it would provide the beginnings of a long-term program to examine the effects of treatment and ultimately improve available treatments for BMS.